A number, when increased by 12, is multiplied by 5 to give 400. Find the original number.

Step-by-step solution

1. Let the original number be $x$.
2. Write the relation: $(x+12)\times 5=400$.
3. Divide both sides by 5 to isolate the parenthesis: $x+12=80$.
4. Subtract 12 from both sides to solve for $x$: $x=68$.
5. Check: $(68+12)\times 5=80\times 5=400$, which satisfies the condition.

Concept tested: Linear equation solving

Published 13 October 2026 · How this solution was prepared and checked